We have addictive personalities, some more others less... We simply like doing things that bring us pleasure, excitement. Some find it in food, others in alcohol and drugs, another ones in sex or porn...
Orgasm usually brings the most intensive feelings of pleasure, therefore it is not surprising that we can get addicted to sex or porn quite fast.
Generally in addiction, the more we experience pleasure the more our system gets desensitized to the same stimuli... the more we want it, the more we have to repeate it... Eventually in order to feel the same satisfaction we have to increase frequency or amount...
So first, we start with small amount - of food, alcohol, drugs, sex and porn, but as time goes we are increasing the amount and/or frequency. After a while we realize that it is not so easy to stop, when we try to stop suddenly we fall in depression, fatigue, irritability, cravings, anxiety,...
Then we have a problem, especially with drugs, alcohol and food. We become dysfunctional, our health suffers, we are burden to society and so forth...
Addiction to porn usually results in relationship problems and also in impotency. You go out with a great sexy girl, there are great vibes, you take her home - and nothing happens, your dick refuses to get up... She leaves disappointed, you turn your porn on - and suddenly everything is "ok" again...
So there is a big problem with addiction in general, just because you like some naked pictures today doesn't mean that you can't be full blown addict couple of years down the road....
What's the solution? IMO there is no need to stop watching naked pictures or porn completely. After all, having orgasm several times per week is healthy both mentally and physically. The key is rather in being moderate - not too much so you don't become lonely addict, and not too little so you don't become creepy-nervous-wrack-pervert, hiding your soul under the wings of great and pure religion... As long as you can rely on your best friend - your dick - to get up and be useful in most intimate situations with the girl you want, you shouldn't worry much about seeing some other pussies here and there on the monitor...